A virtual network is a logical segment of a physical network, in particular of a local area network (LAN). For example, virtual local area networks (VLANs) are described in the IEEE 802.1q standard, which extends the conventional Ethernet standard IEEE 802.1 by an additional packet header which comprises, among others, a VLAN identification tag. Switches and other active network components, which are compatible with the IEEE 802.1q standard only pass data packets through a network port that is configured to a VLAN with a VLAN tag corresponding to the one contained in a packet header.
Virtual networks can be used, for example, to create secure, closed networks within insecure, open networks such as the Internet. In addition, virtual networks can be used to reduce the number of network collisions between data packets and hence improve the network performance.
However, in order to achieve these and similar beneficial objectives, network nodes, for example computers connected to the network, and network equipment, for example switches, should be configured properly. For example, a computer needs a valid and unique address within an virtual network. In addition, the computer should be be configured with valid addresses of important service nodes such as mail or web servers, for example. Switches, routers and other network equipment need to be configured with proper virtual network port assignments, among other. Such a configuration process is tedious and error-prone.
As a consequence, only few virtual networks are configured by network administrators in practice. In addition, network nodes are hardly ever moved from one virtual network to another. This is in contrast to some of the objectives that could be achieved by virtual networks, for example isolating misbehaving network nodes or adjusting virtual networks to changing performance requirements.
Consequently, there exists a need for improved methods for operating virtual networks and data network systems.